“…It is regrettable that research into clinical psychopathology, the core of the discipline of psychiatry, has been back-staged by the ' atheoretical ' approach of current classifications. In the context of the ongoing debate about the future shapes of DSM and ICD, it may be of interest to revisit some halfforgotten earlier concepts, such as Kraepelin's idea of strata (' registers ') of psychopathology (Kraepelin, 1920), or the hierarchical ' classes of personal illness ' proposed by Foulds (1976). Without advocating their ' re-make ', we can perhaps extract from the perspective of such models biometrically testable propositions about the ways in which syndromes and symptoms segregate and recombine with each other to form patterns of personal illness, rather than an assemblage of unrelated ' disorders '.…”